The invention relates to a home trainer designed to accommodate a bicycle, comprising a brakable drive roll incorporated in a frame, which can be mounted in a friction coupling with a driven wheel of the bicycle.
Such a home trainer is known in practice. One problem with the known home trainer occurs when changing the bicycle mounted in the home trainer; positioning the drive roll such as to realize the desired friction coupling with the driven wheel of the bicycle involves some rather complicated operations. Another problem is that the required cycling energy to be produced by the user when using the home trainer is usually adjusted by means of a brake which is susceptible to wear.
It is the object of the invention to eliminate the problems of the prior art home trainer and to attain advantages that will be explained hereinbelow.
In a first aspect, the home trainer according to the invention is characterized in that on the frame a sub-frame is provided that is rotatable about a first pivoting point, the drive roll being mounted in the sub-frame, and in that the frame is further provided with a handle rotatable about a second pivoting point, which is adjustable between an operational position wherein the handle pushes the sub-frame towards the wheel such that the drive roll and the wheel maintain the friction coupling, and a neutral position wherein the handle releases the sub-frame such that the drive roll and the wheel do not engage. Among other things, this measure provides a very simple manner of changing a bicycle, while reliably and easily realizing a suitable friction coupling between drive roll and bicycle wheel, even if the newly mounted bicycle has different wheel sizes.
This is promoted particularly in the embodiment that is preferred, and which is characterized in that the handle is provided with an adjustable tuning knob for determining the position of the sub-frame in the operational position.
A mechanically reliable, low-cost manufactured embodiment of the home trainer according to the invention is characterized in that at the side directed towards the sub-frame, the tuning knob is provided with a bush, and in that the sub-frame has a sliding rim designed to intermate with the bush, the sliding rim terminating in a recess which, when the bush is placed therein, determines the operational position of the handle.
In a further aspect of the invention the home trainer is characterized in that the drive roll is coupled with a flywheel that conducts at least partially magnetic lines of flux, and in that further a position-adjustable magnet is provided which is located near the flywheel. In this manner a wear-resistant brake is provided, allowing the continuous adjustment of the home trainer to a desirable load such as requisite for the rotation of the drive roll.
This is preferably achieved by the magnet being adjustable to a position between a neutral position near a pivoting point of the flywheel and a maximal brake position near the outer circumference of the flywheel. Desirably, the flywheel is provided with recesses, preferably over a periphery located near the neutral position of the magnet. In this manner a very effective cooling of the flywheel is obtained.
It is further preferred that the flywheel comprise an aluminium disc and moreover, that the flywheel be substantially made of steel.
The control of the home trainer according to the invention may be embodied simply such that the magnet is coupled with a spring-loaded cable and that the magnet is adjustable by operating the cable.